Currently, electronic products in the field of communication are made smaller with more integrated functions. As a result, spacings between internal electronic elements of the electronic products are smaller than before. In actual practice, a plastic sealing technique is required to be implemented onto the electronic elements in order to solidify a connection between the electronic elements and a printed circuit board (PCB) for preventing entry of external dust into the electronics elements so as to avoid electricity leakage and interference among the electronic elements.
Current manufacturing process of the thermoplastic sealing applies the surface mount technology (SMT) on a surface of the PCB to produce a printed circuit board assembly (PCBA), filling on plastic materials on a top surface of the PCBA to form a molding layer, and cutting the PCBA after the PCBA is solidified so as to obtain a system in package (SiP) module, in which no other subsidiary films or materials are attached upon electronic units that are mounted on the PCB. Electromagnetic shielding is implemented typically by sputtering a metal layer to form a film or by attaching the film onto the SiP module after the aforesaid plastic sealing, thereby achieving the effect of electromagnetic protection.
However, the process of implementing the electromagnetic shielding by sputtering to form the film after the aforesaid plastic sealing is complicated. For example, a binding force is difficult to be controlled when sputtering to form the film. Therefore, the manufacturing process of the SiP module becomes more complicated.